Scientists Urge Action Against Hessian Fly

By Scout Nelson

The Hessian fly (Mayetiola destructor), one of North America’s earliest invasive insect pests, continues to pose challenges for small grain producers in regions where wheat, barley, and rye are grown.

Originating in the Fertile Crescent, the pest is believed to have arrived in North America during the American Revolution in the straw bedding of Hessian mercenaries, earning its name “Hessian fly.”

Today, the Hessian fly is found across most areas of North America where small grains are cultivated. Populations can be effectively managed with fly-resistant wheat varieties, seeding after the fly-free date, and destroying volunteer plants to eliminate the “green bridge” that allows pests to migrate between crops.

In recent years, particularly in northwestern Minnesota and northeastern North Dakota, Hessian fly infestations have drawn concern from crop advisors. Researchers suggest that reduced tillage due to dry fall conditions and unremoved volunteer wheat may have created favorable conditions for pest survival.

Additionally, covered crops like winter rye seeded before the fly-free date and not terminated early enough can serve as a breeding ground for the pest.

To better understand the issue, Drs. Janet Knodel and Anitha Chirumamilla initiated a Hessian fly monitoring network in North Dakota in 2023 as part of their Integrated Pest Management (IPM) research.

Using pheromone-laced sticky traps, their findings confirm that the Hessian fly is now widespread across the state, with the highest concentrations in northeastern North Dakota, where numbers have steadily increased year-over-year. Their data are available in the 2024 Summary Report and the September 19th issue of NDSU’s Crop & Pest Report.

Experts emphasize that the same trends likely extend into northwestern Minnesota, and while there is no cause for alarm, awareness and prevention are key. Growers are advised to:

• Seed winter cereals after the fly-free date.
• Destroy volunteer grains early to prevent pest migration.

By following these preventive measures, producers can protect their crops, minimize losses, and reduce the spread of Hessian fly infestations in future growing seasons.

Photo Credit:gettyimages-nicolas